In several technical fields there is a need for correct alignment of various components and machines relative to each other. In operation of, for example, large motors, pumps, and similar equipment it is necessary that a first rotary component, such as an output shaft, of a driving unit, in the form of, for example, a motor is aligned correctly with respect to a second rotary component, such as an input shaft, of a driven unit in the form of, for example, a pump. In this way, the output power of the motor can be transmitted via the rotational movement of the motor shaft to the input shaft of the pump in an optimal manner. Any misalignment between the two shafts can result in poor efficiency and increased risk of wear and damage to the motor and the pump.
In the above-mentioned technical field, there is consequently a requirement for correct alignment of the output shaft of the motor relative to the input shaft of the pump. It should be noted in this respect that the two shafts can give rise to alignment errors of generally two different kinds. More specifically, the shafts may be arranged with a specific angle relative to each other, which is called angular error, i.e. a “horizontal angular error” and a “vertical angular error”. Secondly, even if the shafts are parallel to one another they might be somewhat offset relative to each other so as to extend along two separate directions, i.e. in parallel. This is called “horizontal offset” and “vertical offset”. If these errors exceed predetermined threshold values, one can assume that the shafts, and their associated machines, are poorly aligned relative to each other. Their positions must then be adjusted so that a more optimal alignment is achieved.
Thus, there is a general need for systems and methods of aligning various machine units comprising rotary shafts. Such systems and methods can be used for motors, pumps, and similar equipment. Generally, they can be used in power plants, chemical industries, and oil refineries, especially in applications that include high speed, or in applications that include expensive process critical machines which must be aligned.
According to the prior art, described in, for example, SE 524 366 and U.S. Pat. No. 4,518,855, an alignment of two rotary shafts of two machines can be carried out by means of measuring apparatus comprising a first measuring unit arranged for mounting on a first machine and comprising a light source for generating radiation of light in the direction towards a second measuring unit arranged for mounting on a second machine, and also comprising a second light source for generating radiation of light in the direction towards the first measuring unit. Furthermore, each of the measuring units comprises a detection unit for emitted radiation of light. By means of this apparatus, the alignment of the two shafts of the machines can be checked.
The alignment of the components or the machines can be set manually by a user; usually a technician. This has led to a demand for systems which can compute angular errors and offset errors and reproduce these values and the position of the components in a simple and clear manner.
According to prior, traditional art, an alignment of rotary components—e.g. in the form of rotary shafts—could be effected by coupling the components and then placing them together in specific predetermined angular positions along a turn, more specifically in all or some of the angular positions corresponding to 0°, 90°, 270°, and 180° along the turn. This approach was called the “clock method”. Setting out from the measured angular errors and offset errors in respective angular positions, the relative positions of the components could be determined.
It was a disadvantage of the above-mentioned method that it is not always possible as regards all types of machines and the like facilities to position the rotary components, and their measuring units, in all of the above-mentioned angular positions. For example, there may be machine setups where any additional machine part or the like is in the way and prevents the shafts from being set in any of these angular positions. For this reason, the above traditional technology can be complemented with the use of a so-called inclinometer, i.e. an angle meter, which is used for measuring the current angular position of shaft and associated measuring unit, respectively. By this method, it is possible to make use of, in principle, arbitrary angular positions for shaft and measuring unit, respectively, in the alignment. Respective, set angular positions can be measured and are then used for the computations of angular errors and offset errors.
Furthermore, according to the prior art use has also been made of a display unit, comprising inter alia control unit and display connected to the measuring units. In this solution, the control unit receives the values from the measuring units, and then computes the alignment of the components via angular errors and offset errors. These values are reproduced by the display unit via the display as numerical values and graphical information of the components. Icons and indicators showing how the components should be moved and how their position should be adjusted in the alignment can be shown on the display for the convenience of the user.
The above type of measuring equipment is primarily intended to be used when the relevant machines are horizontally oriented, i.e. when the rotary input shafts are arranged along a common horizontal plane.
It should be noted, however, that for many applications the machines are vertically oriented. Hence, there is a need for measuring equipment which has such flexibility as to be usable both for horizontally and vertically aligned components. Analogously herewith, there is a need for measuring equipment which comprises display units which are also adapted for graphical representation of data and images, which can be applied to both horizontally and vertically arranged setups of machines and the like units. It is otherwise difficult for the user to identify the values which according to the display need to be changed as the graphical information on the display and the setup of the physical components are not always consistent.
Thus, it can be established that there is a need for more flexible approaches of aligning rotary components, particularly of aligning setups which are not necessarily horizontally arranged. There is also a market need for increased user friendliness and a clearer representation of the components on the display of a display unit for alignment of shaft driven machines.